Dr. Shades wrote: the scriptures actually require one, the scriptures--at least in that instance--are false.
I think there are Biblical scholars who would dispute that the "scriptures actually require one."
Here's what I found on translation issues regarding the use of the word that is translated as "earth" in English translations of Genesis, from the entry in the Catholic Encyclopedia on the flood:
The Biblical account ascribes some kind of a universality to the Flood. But it may have been geographically universal, or it may have been only anthropologically universal. In other words, the Flood may have covered the whole earth, or it may have destroyed all men, covering only a certain part of the earth. Till about the seventeenth century, it was generally believed that the Deluge had been geographically universal, and this opinion is defended even in our days by some conservative scholars (cf. Kaulen in Kirchenlexikon). But two hundred years of theological and scientific study devoted to the question have thrown so much light on it that we may now defend the following conclusions:
(1) The geographical universality of the Deluge may be safely abandoned.
Neither Sacred Scripture nor universal ecclesiastical tradition, nor again scientific considerations, render it advisable to adhere to the opinion that the Flood covered the whole surface of the earth.
(a) The words of the original text, rendered "earth" in our version, signify "land" as well as "earth"; in fact, "land" appears to have been their primary meaning, and this meaning fits in admirably with Genesis 4, 5 and 10; why not adhere to this meaning also in Genesis 6:9, or the Flood story. Why not read, the waters "filled all on the face of the land", "all flesh was destroyed that moved in the land", "all things wherein there is the breath of life in the land died", "all the high mountains under the whole heaven (corresponding to the land) were covered"? The primary meaning of the inspired text urges therefore a universality of the flood covering the whole land or region in which Noah lived, but not the whole earth.
(b) As to the cogency of the proof from tradition for the geographical universality of the Flood, it must be remembered that very few of the Fathers touched upon this question ex professo. Among those who do so there are some who restrict the Deluge to certain parts of the earth's surface without incurring the blame of offending against tradition.
The earthly paradise, e.g., was exempted by many, irrespective of its location on the top of a high mountain or elsewhere;
the same must be said of the place in which Mathusala must have lived during the Flood according to the Septuagint reading;
St. Augustine knows of writers who exempted the mountain Olympus from the Flood, though he himself does not agree with them;
Pseudo-Justin hesitatingly rejects the opinion of those who restrict the Flood to the parts of the earth actually inhabited by men;
Cajetan revived the opinion that the Flood did not cover Olympus and other high mountains, believing that Genesis spoke only of the mountains under the aerial heaven;
Tostatus sees a figure of speech in the expression of the Bible which implies the universality of the Flood; at any rate, he exempts the earthly Paradise from the Deluge, since Henoch had to be saved.
If the Fathers had considered the universality of the Flood as part of the body of ecclesiastical tradition, or of the deposit of faith, they would have defended it more vigorously. It is true that the Congregation of the Index condemned Vossius's treatise "De Septuaginta Interpretibus" in which he defended, among other doctrines, the view that the Flood covered only the inhabited part of the earth; but theologians of great weight maintained that the work was condemned on account of its Protestant author, and not on account of its doctrine.
(c) There are also certain scientific considerations which oppose the view that the Flood was geographically universal. Not that science opposes any difficulty insuperable to the power of God; but it draws attention to a number of most extraordinary, if not miraculous phenomena involved in the admission of a geographically universal Deluge.
First, no such geological traces can be found as ought to have been left by a universal Deluge; for the catastrophe connected with the beginning of the ice-age, or the geological deluge, must not be connected with the Biblical.
Secondly, the amount of water required by a universal Deluge, as described in the Bible, cannot be accounted for by the data furnished in the Biblical account. If the surface of the earth, in round numbers, amounts to 510,000,000 square kilometres, and if the elevation of the highest mountains reaches about 9000 metres, the water required by the Biblical Flood, if it be universal, amounts to about 4,600,000,000 cubic kilometres. Now, a forty days' rain, ten times more copious than the most violent rainfall known to us, will raise the level of the sea only about 800 metres; since the height to be attained is about 9000 metres, there is still a gap to be filled by unknown sources amounting to a height of more than 8000 metres, in order to raise the water to the level of the greatest mountains.
Thirdly, if the Biblical Deluge was geographically universal, the sea water and the fresh water would mix to such an extent that neither the marine animals nor the fresh-water animals could have lived in the mixture without a miracle.
Fourthly, there are serious difficulties connected with the animals in the ark, if the Flood was geographically universal: How were they brought to Noah from the remote regions of the earth in which they lived? How could eight persons take care of such an array of beasts? Where did they obtain the food necessary for all the animals? How could the arctic animals live with those of the torrid zone for a whole year and under the same roof?
No Catholic commentator will repudiate an explanation merely for fear of having to admit a miracle; but no Catholic has a right to admit Biblical miracles which are not well attested either by Scripture or tradition. What is more, there are traces in the Biblical Flood story which favour a limited extent of the catastrophe: Noah could have known the geographical universality of the Deluge only by revelation; still the Biblical account appears to have been written by an eye-witness. If the Flood had been universal, the water would have had to fall from the height of the mountains in India to the level of those in Armenia on which the ark rested, i.e. about 11,500 feet, within the space of a few days. The fact that the dove is said to have found "the waters . . . upon the whole earth", and that Noah "saw that the face of the earth was dried", leaves the impression that the inspired writer uses the word "earth" in the restricted sense of "land". Attention has been drawn also to the "bough of an olive tree, with green leaves" carried by the dove in her mouth on her second return to the ark.
http://www.newadvent.org/cathen/04702a.htm